Application Potential of Sulfur-Based Autotrophic Denitrification in Low Carbon Wastewater Treatment: Efficiency, Cost and Greenhouse Gas Emission Reduction

With the continuous improvement of wastewater treatment standards, advanced nitrogen removal from municipal wastewater treatment plant effluents faces severe challenges. This paper systematically analyzes the application potential of sulfur-based autotrophic denitrification (SAD) technology in advanced wastewater treatment, focusing on its denitrification efficiency, operational costs, and carbon reduction benefits. Compared to conventional heterotrophic denitrification (HD), SAD technology demonstrates significant advantages, including high denitrification efficiency, low operational costs, low sludge production, and low CO2 emission, through the reduction of external organic carbon source addition and energy consumption. Among the autotrophic denitrification processes, SAD has the highest denitrification rate with low cost and low safety risk. Through sulfur source selection and process optimization, the denitrification rate could reach 1.2 kg N/m3·d, and the accumulation of byproducts can be effectively controlled. As calculated, SAD can reduce over 55% sludge production, reduce 50–80% operational costs, and reduce over 80% greenhouse gas (GHG) emissions. Despite challenges such as long start-up periods, SAD technology shows promising application prospects for advanced treatment of low C/N ratio wastewater. Future research should focus on process optimization and scale-up engineering applications to promote the large-scale implementation of this technology.